Pat Summit...

and Glen Campbell too...

In his first interview since being diagnosed with Alzheimer's in June, the singer told ABC's Terry Moran that he has been "blessed" to have five successful decades in music.

Regarding his health, Campbell revealed he hasn't yet "felt" the effects of the degenerative disease, which robs people of their memory.

"I've always been forgetful anyway," he said in the interview, which aired on "Nightline" on Tuesday. "I'm only what — 78?"

Campbell's wife, Kim Wollen, jumped in to correct him: "75."

"Oh, so I've got a couple more," he joked back.

Wollen was on-hand to help her husband with certain questions he had difficulty answering, like the details of their relationship.

"Did you find me or I find you?" he asked her. "I think we found each other," she said.

Campbell also discussed his new album, "Ghost of the Canvas," and his upcoming farewell tour, which kicks off at the end of August.

"Music is a natural memory aid, and we're finding out, we think it really does help his memory and help keep him from declining," Wollen told Moran.

"So it's really good for him and all the love he gets from all the fans is really encouraging, so that's why we want to do it as long as we can, because it's healthy for all of us. Music is good medicine."